f2fs: compress: add nocompress extensions support

When we create a directory with enable compression, all file write into
directory will try to compress.But sometimes we may know, new file
cannot meet compression ratio requirements.
We need a nocompress extension to skip those files to avoid unnecessary
compress page test.

After add nocompress_extension, the priority should be:
dir_flag < comp_extention,nocompress_extension < comp_file_flag,
no_comp_file_flag.

Priority in between FS_COMPR_FL, FS_NOCOMP_FS, extensions:
   * compress_extension=so; nocompress_extension=zip; chattr +c dir;
     touch dir/foo.so; touch dir/bar.zip; touch dir/baz.txt; then foo.so
     and baz.txt should be compresse, bar.zip should be non-compressed.
     chattr +c dir/bar.zip can enable compress on bar.zip.
   * compress_extension=so; nocompress_extension=zip; chattr -c dir;
     touch dir/foo.so; touch dir/bar.zip; touch dir/baz.txt; then foo.so
     should be compresse, bar.zip and baz.txt should be non-compressed.
     chattr+c dir/bar.zip; chattr+c dir/baz.txt; can enable compress on
     bar.zip and baz.txt.

Signed-off-by: Fengnan Chang <changfengnan@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Documentation/filesystems/f2fs.rst

@@ -281,6 +281,18 @@ compress_extension=%s	 Support adding specified extension, so that f2fs can enab
 			 For other files, we can still enable compression via ioctl.
 			 Note that, there is one reserved special extension '*', it
 			 can be set to enable compression for all files.
+nocompress_extension=%s	   Support adding specified extension, so that f2fs can disable
+			 compression on those corresponding files, just contrary to compression extension.
+			 If you know exactly which files cannot be compressed, you can use this.
+			 The same extension name can't appear in both compress and nocompress
+			 extension at the same time.
+			 If the compress extension specifies all files, the types specified by the
+			 nocompress extension will be treated as special cases and will not be compressed.
+			 Don't allow use '*' to specifie all file in nocompress extension.
+			 After add nocompress_extension, the priority should be:
+			 dir_flag < comp_extention,nocompress_extension < comp_file_flag,no_comp_file_flag.
+			 See more in compression sections.
+
 compress_chksum		 Support verifying chksum of raw data in compressed cluster.
 compress_mode=%s	 Control file compression mode. This supports "fs" and "user"
 			 modes. In "fs" mode (default), f2fs does automatic compression
@@ -817,13 +829,30 @@ Compression implementation
   all logical blocks in cluster contain valid data and compress ratio of
   cluster data is lower than specified threshold.
 
-- To enable compression on regular inode, there are three ways:
+- To enable compression on regular inode, there are four ways:
 
   * chattr +c file
   * chattr +c dir; touch dir/file
   * mount w/ -o compress_extension=ext; touch file.ext
   * mount w/ -o compress_extension=*; touch any_file
 
+- To disable compression on regular inode, there are two ways:
+
+  * chattr -c file
+  * mount w/ -o nocompress_extension=ext; touch file.ext
+
+- Priority in between FS_COMPR_FL, FS_NOCOMP_FS, extensions:
+
+  * compress_extension=so; nocompress_extension=zip; chattr +c dir; touch
+    dir/foo.so; touch dir/bar.zip; touch dir/baz.txt; then foo.so and baz.txt
+    should be compresse, bar.zip should be non-compressed. chattr +c dir/bar.zip
+    can enable compress on bar.zip.
+  * compress_extension=so; nocompress_extension=zip; chattr -c dir; touch
+    dir/foo.so; touch dir/bar.zip; touch dir/baz.txt; then foo.so should be
+    compresse, bar.zip and baz.txt should be non-compressed.
+    chattr+c dir/bar.zip; chattr+c dir/baz.txt; can enable compress on bar.zip
+    and baz.txt.
+
 - At this point, compression feature doesn't expose compressed space to user
   directly in order to guarantee potential data updates later to the space.
   Instead, the main goal is to reduce data writes to flash disk as much as

fs/f2fs/f2fs.h

@@ -151,8 +151,10 @@ struct f2fs_mount_info {
 	unsigned char compress_level;		/* compress level */
 	bool compress_chksum;			/* compressed data chksum */
 	unsigned char compress_ext_cnt;		/* extension count */
+	unsigned char nocompress_ext_cnt;		/* nocompress extension count */
 	int compress_mode;			/* compression mode */
 	unsigned char extensions[COMPRESS_EXT_NUM][F2FS_EXTENSION_LEN];	/* extensions */
+	unsigned char noextensions[COMPRESS_EXT_NUM][F2FS_EXTENSION_LEN]; /* extensions */
 };
 
 #define F2FS_FEATURE_ENCRYPT		0x0001

fs/f2fs/namei.c

@@ -287,14 +287,16 @@ static void set_compress_inode(struct f2fs_sb_info *sbi, struct inode *inode,
 						const unsigned char *name)
 {
 	__u8 (*extlist)[F2FS_EXTENSION_LEN] = sbi->raw_super->extension_list;
-	unsigned char (*ext)[F2FS_EXTENSION_LEN];
+	unsigned char (*noext)[F2FS_EXTENSION_LEN] = F2FS_OPTION(sbi).noextensions;
-	unsigned int ext_cnt = F2FS_OPTION(sbi).compress_ext_cnt;
+	unsigned char (*ext)[F2FS_EXTENSION_LEN] = F2FS_OPTION(sbi).extensions;
+	unsigned char ext_cnt = F2FS_OPTION(sbi).compress_ext_cnt;
+	unsigned char noext_cnt = F2FS_OPTION(sbi).nocompress_ext_cnt;
 	int i, cold_count, hot_count;
 
 	if (!f2fs_sb_has_compression(sbi) ||
-			is_inode_flag_set(inode, FI_COMPRESSED_FILE) ||
 			F2FS_I(inode)->i_flags & F2FS_NOCOMP_FL ||
-			!f2fs_may_compress(inode))
+			!f2fs_may_compress(inode) ||
+			(!ext_cnt && !noext_cnt))
 		return;
 
 	down_read(&sbi->sb_lock);
@@ -311,7 +313,15 @@ static void set_compress_inode(struct f2fs_sb_info *sbi, struct inode *inode,
 
 	up_read(&sbi->sb_lock);
 
-	ext = F2FS_OPTION(sbi).extensions;
+	for (i = 0; i < noext_cnt; i++) {
+		if (is_extension_exist(name, noext[i], false)) {
+			f2fs_disable_compressed_file(inode);
+			return;
+		}
+	}
+
+	if (is_inode_flag_set(inode, FI_COMPRESSED_FILE))
+		return;
 
 	for (i = 0; i < ext_cnt; i++) {
 		if (!is_extension_exist(name, ext[i], false))

fs/f2fs/super.c

@@ -148,6 +148,7 @@ enum {
 	Opt_compress_algorithm,
 	Opt_compress_log_size,
 	Opt_compress_extension,
+	Opt_nocompress_extension,
 	Opt_compress_chksum,
 	Opt_compress_mode,
 	Opt_compress_cache,
@@ -223,6 +224,7 @@ static match_table_t f2fs_tokens = {
 	{Opt_compress_algorithm, "compress_algorithm=%s"},
 	{Opt_compress_log_size, "compress_log_size=%u"},
 	{Opt_compress_extension, "compress_extension=%s"},
+	{Opt_nocompress_extension, "nocompress_extension=%s"},
 	{Opt_compress_chksum, "compress_chksum"},
 	{Opt_compress_mode, "compress_mode=%s"},
 	{Opt_compress_cache, "compress_cache"},
@@ -493,6 +495,43 @@ static int f2fs_set_test_dummy_encryption(struct super_block *sb,
 }
 
 #ifdef CONFIG_F2FS_FS_COMPRESSION
+/*
+ * 1. The same extension name cannot not appear in both compress and non-compress extension
+ * at the same time.
+ * 2. If the compress extension specifies all files, the types specified by the non-compress
+ * extension will be treated as special cases and will not be compressed.
+ * 3. Don't allow the non-compress extension specifies all files.
+ */
+static int f2fs_test_compress_extension(struct f2fs_sb_info *sbi)
+{
+	unsigned char (*ext)[F2FS_EXTENSION_LEN];
+	unsigned char (*noext)[F2FS_EXTENSION_LEN];
+	int ext_cnt, noext_cnt, index = 0, no_index = 0;
+
+	ext = F2FS_OPTION(sbi).extensions;
+	ext_cnt = F2FS_OPTION(sbi).compress_ext_cnt;
+	noext = F2FS_OPTION(sbi).noextensions;
+	noext_cnt = F2FS_OPTION(sbi).nocompress_ext_cnt;
+
+	if (!noext_cnt)
+		return 0;
+
+	for (no_index = 0; no_index < noext_cnt; no_index++) {
+		if (!strcasecmp("*", noext[no_index])) {
+			f2fs_info(sbi, "Don't allow the nocompress extension specifies all files");
+			return -EINVAL;
+		}
+		for (index = 0; index < ext_cnt; index++) {
+			if (!strcasecmp(ext[index], noext[no_index])) {
+				f2fs_info(sbi, "Don't allow the same extension %s appear in both compress and nocompress extension",
+						ext[index]);
+				return -EINVAL;
+			}
+		}
+	}
+	return 0;
+}
+
 #ifdef CONFIG_F2FS_FS_LZ4
 static int f2fs_set_lz4hc_level(struct f2fs_sb_info *sbi, const char *str)
 {
@@ -566,7 +605,8 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
 	substring_t args[MAX_OPT_ARGS];
 #ifdef CONFIG_F2FS_FS_COMPRESSION
 	unsigned char (*ext)[F2FS_EXTENSION_LEN];
-	int ext_cnt;
+	unsigned char (*noext)[F2FS_EXTENSION_LEN];
+	int ext_cnt, noext_cnt;
 #endif
 	char *p, *name;
 	int arg = 0;
@@ -1069,6 +1109,30 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
 			F2FS_OPTION(sbi).compress_ext_cnt++;
 			kfree(name);
 			break;
+		case Opt_nocompress_extension:
+			if (!f2fs_sb_has_compression(sbi)) {
+				f2fs_info(sbi, "Image doesn't support compression");
+				break;
+			}
+			name = match_strdup(&args[0]);
+			if (!name)
+				return -ENOMEM;
+
+			noext = F2FS_OPTION(sbi).noextensions;
+			noext_cnt = F2FS_OPTION(sbi).nocompress_ext_cnt;
+
+			if (strlen(name) >= F2FS_EXTENSION_LEN ||
+				noext_cnt >= COMPRESS_EXT_NUM) {
+				f2fs_err(sbi,
+					"invalid extension length/number");
+				kfree(name);
+				return -EINVAL;
+			}
+
+			strcpy(noext[noext_cnt], name);
+			F2FS_OPTION(sbi).nocompress_ext_cnt++;
+			kfree(name);
+			break;
 		case Opt_compress_chksum:
 			F2FS_OPTION(sbi).compress_chksum = true;
 			break;
@@ -1093,6 +1157,7 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
 		case Opt_compress_algorithm:
 		case Opt_compress_log_size:
 		case Opt_compress_extension:
+		case Opt_nocompress_extension:
 		case Opt_compress_chksum:
 		case Opt_compress_mode:
 		case Opt_compress_cache:
@@ -1147,6 +1212,13 @@ default_check:
 	}
 #endif
 
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+	if (f2fs_test_compress_extension(sbi)) {
+		f2fs_err(sbi, "invalid compress or nocompress extension");
+		return -EINVAL;
+	}
+#endif
+
 	if (F2FS_IO_SIZE_BITS(sbi) && !f2fs_lfs_mode(sbi)) {
 		f2fs_err(sbi, "Should set mode=lfs with %uKB-sized IO",
 			 F2FS_IO_SIZE_KB(sbi));
@@ -1697,6 +1769,11 @@ static inline void f2fs_show_compress_options(struct seq_file *seq,
 			F2FS_OPTION(sbi).extensions[i]);
 	}
 
+	for (i = 0; i < F2FS_OPTION(sbi).nocompress_ext_cnt; i++) {
+		seq_printf(seq, ",nocompress_extension=%s",
+			F2FS_OPTION(sbi).noextensions[i]);
+	}
+
 	if (F2FS_OPTION(sbi).compress_chksum)
 		seq_puts(seq, ",compress_chksum");